The United States joined World War 1 first because German U-Boats sunk the <em>Louisiana</em> Ship which was carrying 1962 passengers where 1198 lost their lives. The ship had 128 Americans as it left for Liverpool from New-York on May 1st, 1915 which resulted in the rise of a lot of outrage in the U.S. Secondly, Germany had resumed restricted submarine warfare in the Atlantic through a policy initiated in 1915 which allowed U-Boats to hunt and sink merchant ships without warning. The entry of the U.S in the war resulted in a boom in the economy as industries enjoyed an increase in their profits. The war further impacted change on the social, economic and political as the U.S emerged as a world military and industrial leader. There was also a rise in immigrants from other European countries with estimates of 300,000-500000 African Americans moving North to the cities.
